Operating mechanism for an electric circuit interrupter



a i Ah.

Nov. 22, 1960 L. L. BAIRD ETAL 2,961,509

OPERATING MECHANISM FOR AN ELECTRIC CIRCUIT INTERRUPTER Filed Feb. 4,1959 5 Sheets-Sheet l CLO-SEO Inventors: Leslie L... Baird, -J'Ralph J.Baskerville be; I WMAMW/ weir Attorneg.

Nov. 22, 1960 L. BAIRD ETAL 2,961,509

OPERATING MECHANISM FOR AN ELECTRIC CIRCUIT INTERRUPTER Filed Feb. 4.1959 5 Sheets-Sheet 2 Fig.2.

TR/PPED OPE/V CLO'S/NG I a l i Q Invent rs: III'I'II, L, e S I e T d 7 1h J. Bask mej 5 a p heif'Attorneg.

Nov. 22, 1960 L. L. BAIRD ETAL OPERATING MECHANISM FOR AN ELECTRICCIRCUIT INTERRUPTER Filed Feb. 4, 1959 5 Sheets-Sheet 3 Inventors:

Leslie J... Baird, Ralph J. Baskerville,

Their Attorney.

Nov. 22, 1960 L. L. BAIRD ETAL 2,961,509

OPERATING MECHANISM FOR AN ELECTRIC CIRCUIT INTERRUPTER Filed Feb. 4,1959 5 Sheets-Sheet 4 CLOSED Inventor-s: Leslie L.. Baird,

alph J. Baskerville,

by h

heir Attorneg Nov. 22, 1960 1.. L. BAIRD ETAL 2,961,509

/ OPERATING MECHANISM FOR AN ELECTRIC CIRCUIT INTERRUPTER Filed Feb. 4,1959 s Sheets-Sheet 5 OPEN-RESET CLOSING Inventors: Leslie J... Baird,jRalph J. Basker-ville United States Patent OPERATING MECHANISM FOR ANELECTRIC CIRCUIT INTERRUPTER Leslie L. Baird, Swarthmore, and Ralph J.Baskerville,

Drexel Hill, Pa., assignors to General Electric Company, a corporationof New York Filed Feb. 4, 1959, Ser. No. 791,076

41 Claims. (Cl. 200106) This invention relates to an electric circuitinterrupter or breaker, and more particularly it relates to a circuitbreaker operating mechanism wherein a spring is arranged to releasestored energy to the mechanism for obtaining a quick-action circuitclosing or making operation.

Such stored energy mechanisms are commonly used in low-voltage aircircuit breakers for driving a movable switch member between open andclosed circuit positions. Mechanical energy is first accumulated in thespring by the controlled action of a pivotally movable operating memberconnected thereto. By moving the operating member from a reset positionto an operated position with the mechanism in a releasably latchedcondition, the spring is stressed and accumulates energy the release ofwhich imp-arts quick and positive switch closing movement to themechanism. It is a general object of the present invention to provide animproved circuit breaker operating mechanism of this type.

A more specific object of the invention is to provide an operatingmechanism of this type wherein the spring must be substantially fullystressed or charged and will always release a predetermined constantamount of stored energy for imparting switch closing movement to themechanism regardless of liberal manufacturing tolerances, variations inthe rate at which the operating member is moved to its operatedposition, and changes in the frictional forces of the mechanism due towear.

Another object of this invention is the provision of an improvedoperating mechanism wherein the operating member cannot be returned fromits operated to its reset position while the switch member is in itsclosed circuit position, whereby the mechanism must be unlatched inorder to obtain switch opening movement thereof.

Still another object is the provision of an improved operating mechanismutilizing electromagnetic means for moving the operating member from itsreset to its operated positions, said movement of the operating membercontrolling the accumulation of energy in the spring and efiectingrelease of energy thus accumulated for producing switch closing movementof the mechanism.

It is still another object of the invention to provide electromagneticmeans comprising a solenoid and a rigid armature which is adapted to bedirectly and positively connected to the pivotally movable operatingmember of the circuit breaker operating mechanism for moving theoperating member between different angular positions.

A further object is the provision of electromagnetic means, comprising asolenoid, a magnetizable yoke and a movable plunger, for stressing orcharging a spring wherein the magnetic force acting on the plungerincreases relatively linearly throughout the charging operation.

A specific object of the present invention is to provide improvedelectromagnetic apparatus comprising an electric coil wound on a spoolof insulating material, a magnetizable yoke supporting the spool and aplunger disposed for movement within the spool, the electromagneticapparatus being extremely simple and inexpensive to manufacture andassemble.

in carrying out our invention in one form, we provide a circuitinterrupter including a movable switch member, a releasably latchedoperating mechanism connected to the switch member, and an operatingmember disposed for pivotal movement between reset and operatedpositions. The operating mechanism includes a spring connected to theoperating member, the spring being charged and exerting a switch closingforce on the mechanism during movement of the operating member towardits operated position. We provide means for restraining the switchmember in an open circuit position until the operating member reaches apredetermined point near its operated position whereupon the switchmember is released and the operating mechanism undergoes quick-actionswitch closing movement in accordance with the force being exerted bythe spring. In addition, the mechanism is arranged so that the operatingmember is blocked in its operated position in response to circuitclosing movement of the switch member, whereby the operating mechanismhas to be unlatched in order to obtain a circuit opening operation andpermit return of the operating member to its reset position.

In one aspect of our invention, the operating member is moved from itsreset to its operated position by electromagnetic means comprising asolenoid and a cooperating rigid armature. The armature, which is movedlongitudinally by the force of magnetic attraction upon energization ofthe solenoid, is connected to the operating member at a point definingan arcuate path while the operating member is being moved toward itsoperated position. We provide means for guiding the rigid armature withleeway for lateral deviation during its longitudinal movement, andpreferably this means comprises the insulating spool of the solenoid inwhich the armature is relatively loosely disposed. A magnetizable yokeis also provided for the solenoid, the yoke and the armature beingconfigured and arranged so as to reduce the nonlinearity of the rate ofincrease of magnetic force experienced by the armature while moving theoperating member. The yoke preferably comprises two parts assembled incooperation with specially constructed grooved flanges of the aforesaidspool for supporting the solenoid.

The invention will be better understood and its various objects andadvantages will be more fully appreciated from the following descriptiontaken in conjunction with the accompanying drawings in which:

Fig. l is a side elevation of a circuit interrupter having an operatingmechanism constructed in accordance with one embodiment of theinvention, the circuit interrupter being shown in its closed circuitposition;

Fig. 2 is a simplified side elevation of the circuit interrupter of Fig.l with the operating mechanism and the switch member of the interrupterbeing shown in tripped-open positions;

Fig. 3 is a partial side elevation of the circuit interrupter of Fig. 1showing the operating mechanism in its open-reset position;

Fig. 4 is a side elevation of the operating mechanism shown intermediateits open-reset and closed positions just prior to snap-action switchclosing movement thereof;

Fig. 5 is a section taken along lines 5-5 of Fig. 1;

Fig. 6 is a section taken along lines 66 of Fig. 5;

Fig. 7 is a view similar to that of Fig. 1 but illustrating a manuallyoperable operating mechanism constructed in accordance with anotherembodiment of our invention;

Fig. 8 is a partial side elevation of the operating mechanism of Fig. 7with the mechanism moved to its open-reset position; and

Fig. 9 is a partial side elevation of the operating mechanism of Fig. 7,the mechanism being shown intermediate its open-reset and closedpositions just prior to snap-action switch closing movement thereof.

Referring now to Fig. l, we have shown an electric circuit breaker orinterrupter comprising a frame member 11 supporting a base member 12 ofelectric insulating material, a relatively stationary contact or switchmember 13 mounted on the base, a bracket 14 mounted on the base inspaced relation to the stationary contact member, a movable contact orswitch member 15 pivotally supportedby bracket 14 and disposed incooperative relationship with the stationary switch member 13, andactuating means such as a crossbar 16 coupled to the movable switchmember 15 for moving this member into and out of circuit-makingengagement with the stationary switch member 13. Movement of the switchmember 15 into and out of engagement with the member 13 closes andopens, respectively, an electric circuit represented by'conductors 17and 18. The components 13, 14 and 15 comprise thecontact structure ofone pole unitrof an'alternating or direct current circuit interrupter,and other pole units substantially identical to that shown could bemounted on the frame member 11 for gang operation by the common crossbar16. The particular contact structure that has been shown in thedrawings" for the purpose of illustrating the present invention is thesubject matter of the copending patent application of Leslie'L. Baird,S.N. 764,642 filed on October 1, 1958, and assigned to the assignee ofthe present invention.

Movement of the switch member15 between its closed circuit position(Fig. 1) and its open circuit position (Fig. 2) is controlled by anoperating mechanism which is connected to the switch member by means ofan elongated connecting member 19 pinned to a link 20 which in turn isfirmly affixed to the crossbar 16. The operating mechanism comprises aplurality of interconnected movable members one of which is a guidemember 21 pivotally mounted on the frame member 11 by means of a rod 22fixedly supported thereby. The remaining members constitute aforce-transmitting linkage mechanism 23 pivotally fastened by a pin 24to theconnecting member 19 and hence to the movable switch member 15.The pin 24- is supported for movement along a predetermined arcuate pathby an output crank 25 of the. mechanism' which is pivotally mounted onthe frame member 11 at 26. The various illustrated parts of the operatmgmechanism, with the exception of the guide member 21, preferably areprovided in identical pairs so that the entire mechanism is symmetricalwith respect to a vertical plane parallel to the plane of the drawings,with the guide member 211 being disposed in the plane of symmetry. Theoutput crank 25 actually is a U-shaped member, the two identical,spaced-apart upstanding parts of which are rigidly interconnected by atransverse part 25a.

The operating mechanism also includes at least one helical tensionspring 27 arranged to release stored energy to the mechanism forimparting quick-action switch closing and opening movement thereto.Accumulation of energy in the spring 27 is controlled by a movableope-rating member 28 which is pivotally mounted on the frame member 11by means of the rod 22 afiixed thereto. The operating member 23preferably comprises two identical upstanding parts, only the far onebeing shown, rigldly interconnected by a pair of transverse sections 28aand 28b. The spring 27 interconnects the operating mechanism and alaterally extending pin 29 carried by the operating member 23.

The operating member 28 is disposed for pivotal movement between twodifierent angular positions at opposite ends of its normal range ofmovement: a first or reset position shown in Fig. 3, and a second oroperated position shown in Fig. 1. While moving to its second oroperated position with the operating mechanism in a releasably latchedcondition (the latching means is described in detail hereinafter), theoperating member will stress or charge the spring 27 and will effectrelease of energy thus stored in the spring for producing switch closingmovement of the mechanism. In order to obtain this movement of theoperating member 28, suitable electroresponsive means such as thesolenoid 30 and co operating armature 31 shown in Figs. 1 and 3 may beemployed, or the operating member may be coupled to a suitably disposedmanually operable handle 32 such as is illustrated in Figs. 79.

In the illustrated embodiments of the invention, the operating mechanismincludes a toggle comprising two links 33 and 34 pivotally joined by apin 35 which forms the knee of the toggle. (Actually, as has beenpointed out hereinbefore, the links 33" and 34 are provided in identicalpairs, and the near one of'the links 34 is omitted in the drawings forthe sake of clarity.) The spring 27 functions as an overcenter spring,and one end of the spring is connected to the pin or toggle knee 35. Oneend of the toggle, specifically the right-hand end of the link 34 asviewed in the drawings is connected to the pin 24 and hence to-theswitch member 15' for moving the switch member between its open andclosed circuit positions. The other end of the toggle, specifically theleft-hand end oflink 33; is supported by a pin 36 for'movement betweentwo'dilferent positions.

The pin 36 is connected to the guide member 21. As the guide membermoves pivotally between predetermined latched and unlatched positions,the pin 36 is carried along a predetermined arcuate path 35p (Fig. 1)with respect to the axis of the supporting rod 22. In Figs. 1 and 3-theguide member'or lever 21 is shown in its latched position where it isreleasably restrained by a latch indentified generally by the referencenumber 37.

In order to close the circuit interrupter, the'operating mechanism isarranged to move the switch member 15 from its open circuit positionitoits closed position with quick and positive action. This is accomplishedby moving the operating member'ZS from its first or reset position (Fig.3) toward its second or operated position (Fig. 1) in response to whichthe overcenter spring 27 is stretched or charged and moves over centerwith respect to the toggle link 33. The spring force being exerted onthe toggle knee 35 willnow produce in toggle link 33' a counterclockwise torque tending to straighten the toggle from its initiallycollapsed condition shown in Fig. 3. Upon release of energy stored inthe spring, the'toggle knee is pulled upward and the toggle undergoessnap-action switch closing movement which rotates the output crank' 25clockwise and drives the switch member 15 to its closed position.

The closed position of the operating mechanism, as can be seen in Fig.1, is determined by the engagement of a pin 38 protruding laterally fromtoggle link 33 with an interfering stop surface 39 of the guide member21, the guide member at this time being firmly held in its latchedposition by the latch 37. Suitable stop and blocking means, to bedescribed hereinafter, are respectively provided for definitelydeterminingthe second position of the operating member 28 and forpreventing the return of the operating member to its first position aslong asv the switch member 15' is closed. As is evident in Fig. l, thesecond position of the operating member 28 is so located in relation tothe toggle after undergoing switch closing movement thereof that theline of action of the overcenter spring force intersects the path 36;;to. be followed by the pin 36 during subsequent movement of the guidemember 21' to its unlatched position. In the closed position of theoperatingvmechanism there is still a substantial amount of energyremaining in the overcenter spring 27, since not all of the storedenergy was given up by this spring while effecting the abovedescribedclosing operation.

As is clearly shown in Fig. l, the. overcenter spring 27 exerts a forceon the guide member 21, by way of toggle link 33 and the pins 36 and38,.tending to drive this member in a clockwise direction from itslatched position. It is the function of the latch 37 to prevent suchmovement by the guide member until a circuit opening operation of theinterrupter is desired. The latch comprises a transversely extendingtrip shaft 40 supported by the frame member 11 for rotary movementbetween a normal position shown in Figs. 1 and 3 and a trip positionshown in Fig. 2. A radially protruding portion or prop 41 of the tripshaft 40 cooperates with an intermediate latch member or catch 42 forreleasably restraining the guide member 21 in its latched position withthe trip shaft in its normal position.

The latch member 42 is pivotally mounted intermediate its ends on atransverse rod 43 which is supported by the frame 11. On one side of therod 43 this member is provided with a stud 44 disposed in self-releasingengagement with the heel of an integral leg 45 of the guide member 21.With the trip shaft 40 in its normal position, the stud 44 of theintermediate latch member 42 is firmly held in engagement with leg 45 ofthe guide member, thereby maintaining the guide member in its latchedposition, by the prop 41 which abuts a roller 46 carried by the latchmember on the other side of rod 43. The latch member 42 preferablycomprises two similar parts (only the near one being shown) that arefirmly joined by the stud 44 and the axle of the roller 46. A tensionspring 47 is provided for biasing the trip shaft 40 in a clockwisedirection to its normal position and for biasing the intermediate latchmember or catch 42 in a clockwise direction into self-releasingengagement with the guide member 21.

The intermediate latch member 42 with its roller 46 and the prop 41 areconstructed and arranged so that the resultant force of action andreaction therebetween is directed normal to the axis of rotation of thetrip shaft 40. To accomplish this result in the illustrated embodimentsof the invention, the prop surface 41a abutting the roller 46 isconformed to a circumferential section of a right cylinder whose axis isthe axis of shaft 40. Consequently, the line of action of the resultantforce transmitted by the prop 41 to the trip shaft, in order to restainthe guide member 21 in its latched position against the force ofovercenter spring 27, intersects the axis of the trip shaft 40 and hasno moment arm with respect thereto. This arrangement helps to eliminateaccidental unlatching operation by the latch 37 upon the occurrence ofany relatively sudden and severe mechanical shock to the circuitinterrupter. The prop 41 is in compression and free of bending stresses,whereby any tendency to distort adversely the circumferential surface41a is relieved.

In order to open the circuit interrupter, the operating mechanism isarranged to move the switch member 15 from its closed circuit positionto its opened circuit position with quick and positive action inresponse to toggle releasing operation of the latching means. Theopening operation is initiated by rotating the trip device 40 in acounterclockwise direction from its normal position (Fig. 1) to itstripped position (Fig. 2). For this purpose any suitable means may beused, such as, for example the schematically illustrated manuallyoperable trip bar 48. Longitudinal movement of the trip bar 48 to theright, as viewed in Fig. 1, causes an adjustablelength terminal portion49 of this bar to strike and tilt a paddle member 54 which is rigidlyaifixed to the trip shaft 40. As a result, the trip shaft is rotatedcounterclockwise and the prop 41 is pivoted away from the roller 46 ofintermediate latch member 42. The force necessary to accomplish thisresult is significantly less than the force being exerted at this timeby the overcenter spring 27 because of the favorable force amplifyingleverage system formed by the interengaging pivotally supported members50, 41, 42 and 21 of the latching means.

The removal of prop 41 from abutting relationship with roller 46 enablesthe intermediate latch member 42 to move counterclockwise about rod 43in accordance with the force applied at its stud 44 by the leg 45 ofguide member 21, whereupon the guide member is no longer restrained inits latched position. The overcenter spring 27 is effective in responseto this guide releasing operation of the latch 37 to drive the guidemember to its unlatched position (Fig. 2) thereby enabling the operatingmechanism to undergo switch opening movement. As the spring releasesenergy during the opening operation, the toggle knee 35 is pulled to theleft (as viewed in Fig. 1) and the pin 36 carried by the guide membermoves upward along its arcuate path 36p. When the pin 36 has passedthrough the line of action of the overcenter spring 27, the togglecollapses and undergoes snap-action switch opening movement. During thisaction the output crank 25 is rotated counterclockwise and the movableswitch member 15 is driven to its open circuit position.

The operating mechanism is shown in a collapsed, tripped-open conditionin Fig. 2. As can be seen in this figure, the open position of theswitch member 15 and the corresponding position of the mechanism outputcrank 25 are determined by the engagement of a bushing 52 located on pin24 with a concave stop surface 53 of the frame member 11. The guidemember 21 is here in its unlatched position which is determined by theengagement of a shoulder 54 of the guide mem her with suitable stopmeans such as the illustrated rod 55. The rod 55 is rigidly afiixed tothe frame 11 and blocks further clockwise movement of the guide member21 about its pivot 22. Since one end of the toggle is connected to thepin 24 and the opposite end is connected through pin 36 to the guidemember 21, the position of the toggle knee 35 at this time isnecessarily fixed. For the reasons which will be explained hereinafter,the operating mechanism is only momentarily in the position in which itis shown in Fig. 2.

During the above-described opening operation, the toggle knee 35 isforced to follow a relatively linear path from its position shown inFig. 1 to its position shown in Fig. 2. This is accomplished byproviding suitable camming means controlled by movement of the guidemember 21 and disposed in cooperation with the toggle. Preferably thecamming means comprises a concave camming surface 56 of the guide member21 which engages a roller 57 connected to the toggle link 34 while theguide member is moving toward its unlatched position. As a result, themovement of the toggle is controlled in a manner to obtain asubstantially uniform rate of energy release by the overcenter spring 27throughout the opening operation, and the spring will manifest arelatively high force gradient in resisting rebound of the movableswitch member 15 from its open circuit position.

The circuit interrupter operating mechanism, in the rst embodiment ofthe invention, is automatically moved by the overcenter tension spring27 from its trippedopen position of Fig. 2 to its open-reset positionshown in Fig. 3. This is accomplished by arranging the mechanism inaccordance with the principle fully explained and claimed in UnitedStates Patent 2,866,872 issued to W. Turner on December 30, 1958. Ifautomatic reset is not desired, as in the case of a manually operablecircuit interrupter such as that illustrated in Figs. 7-9, the operatingmechanism can be arranged differently so that movement of the operatinghandle 32 is required to accomplish the resetting operation. Regardlessof whether it is eifected automatically by the spring 27 or manually byother means, the resetting operation is basically the same: theoperating member 28 is returned to its first or reset position, theguide member 21 is simultaneously driven to its latched position, andthe toggle is moved in its collapsed condition to the position in whichit is shown in Fig. 3.

With the operating mechanism in its tripped-open position, as can beseen in Fig. 2, the overcenter spring" 27 is exerting a forceon theoperating member 28 tending to move this pivotally mounted member in acounterclockwise'direction toward its first or reset position.Counterclockwise movement of the operating member carries pin 29 along apredetermined arcuate path 29p shown in Fig. 3; An arm 65 of the guidemember 21 is disposed, with the guide member in its unlatched position,immediately below the laterally extending pin 29. While the operatingmember is being moved from its first to its second positions, the pin 29engages the upper surface of arm 65 and drives the guide member 21 in acounterclockwise direction about its pivot 22to its latched position.While moving toward its latched position, the guide member, being pinnedat 36 to the toggle link 33, impels the toggle to-its open-resetposition shown in Fig. 3. In attaining this position, the toggle knee 35has followed a path 351' which progressively converges with the arcuatepath 29p of pin 29. Therefore the overcenter tension spring 27, which isconnected between pin 29 and toggle knee 35; progressively shortensduring the resetting operation and releases energy for returning theoperating member 28 to its first position and for driving the guidemember 21 to its latched position.

During the resetting operation of the mechanism, the latch 37 is alsoreset thereby releasably restraining the guide member 21 in its latchedposition. Vfnen the guide member is in its unlatched position (Fig. 2),and during the initial movement of this member toward'its' latchedposition, the intermediate latch member 42 is held in a tilted positionagainst the force of its bias spring 47 by the guide member leg 45 whoselower surface slidably engages a cooperating extension 66 of the member42. The leg 45 slides across the top of stud 44 as the guide memberapproaches its latched position and finally passes beyond this stud,whereupon the intermediate member 42 is free to pivot clockwise on rod43 in accordance with its bias and the stud 4 moves into self-releasingengagement with the heel of leg 45. This enables the trip shaft 40 toreturn to its normal position, and the prop 41 moves into its abuttingdisposition with respect to the roller 46 of latch member 42. See Fig.3. When the operating member 28 is subsequently moved toward its secondor operated position, member 42 will tilt slightly into engagement withprop 41 and the latch 37 is again effective to restrain the guide member21 in its latched position.

The above-described resetting operations cannot take place until themovable switch member of the circuit interrupter has moved from itsclosed circuit position to its open circuit position. This is due to theprovision of blocking means for positively preventing movement of theoperating member 28 from its second or operated position to its first orreset position whenever the switch member is closed. Since the operatingmember is blocked in its second position with the switch member closed,the only way the circuit interrupter can be opened is by actuating thelatching means in consequence of which the operating member is permittedto return to its first position.

The blocking means preferably comprises a pair of cooperating blockingelements 67 and 63 associated with the operating member 28 and themechanism output crank 25, respectively. As can be seen in Fig. 1, theblocking element 67 is an integral limb of the operating member having ablunt end and generally curved edges disposed for movement along apredetermined arcuate path in accordance with the pivotal movement ofthe operating member 28 between its first and second positions. Thecooperating element 68 comprises a lug extending transversely from aprojection of the output crank for movement about pivot 26 in responseto circuit opening and closing movement of the switch member 15. Inother words, the blocking element 68 is actuated by move- 8 ment of pin24 which physically interconnects the output end of the toggle andthemovable switch member 15'.

By moving the operating member 28 from its first position shown in Fig.3 to its second position shown in Fig. 1, a'snap-action switch closingoperation of the mechanism is effected. The blocking element 68 isaccordingly moved into the predetermined path of movement of theblocking element 67 where, as best seen in Fig. 1, it interferes withthe blunt end of element 67 and positively blocks the operating member28 in its second position. When later the latching means is operated torelease the toggle, the mechanism undergoes switch opening movementduring which the element 68 is moved out of the aforesaid predeterminedpath to unblock the operating member 23, as shown in Fig. 2; Only nowcan a resetting operation be undertaken and the operating member movedto its first position (Fig. 3).

Thus, the blocking means which became effective during the closingoperation to releasably restrain the operat ing member 28 in its secondposition, is moved'only in response to a subsequent opening operation tofree the operating member for return to its first position. The blockingmeans is arranged so that movement ofthe operating member 28 toward itsfirst'position is permitted only after the snap-action switch openingmovement of the toggle has been initiated and the movable switch member1515 substantially fully opened, whereby in the first embodim'entof theinvention the automatic resetting operation cannot begin untilafter theopening operation is practically completed.

With the operating mechanism in its open-reset position, the circuitinterrupter can be closed by energizing the illustrated electromagneticmeans which will move theoperating member 28 from its first to itssecond position. The energizing circuit for the electromagnetic meansincludes, for example, a suitable control switch (not shown), a pair ofseparable electric contacts 70 and 71 of a cutofi switch '72, and thecoil of solenoid 34) all connected in series circuit relationship to asuitable source of control power (not shown). Closing the control switchenables current to fiow through the solenoid coil, and the resultingforce of magnetic attraction causes the armature or plunger 31 to moveupwardly from the position in' which it is shown in Fig. 3. This drivesthe operating member 23 toward its second position inresponse to whichenergy is accumulated in the overcenter spring 27 and a switch closingforce is exerted on the toggle.

The actual snap-action switch closing movement of the toggle cannot takeplace before the operating member 23' reaches a predetermined point nearits second position such as is shown in Fig. 4. This is due to theprovision of blocking means for releasably restraining the movableswitch member 15 in its open circuit position until the operating memberis moved past the aforesaid predetermined point, whereupon the switchmember is released and the toggle is able to undergo switch closingmovement in accordance with the force being exerted by the overcenterspring.

The predetermined point at which the blocking means becomes ineffectiveand energy stored in the spring is first released for imparting switchclosing movement to the mechanism is selected in the preferredembodiment of our invention, for example, so that the operating membermust be moved through approximately 97 percent of its total range ofmovement in order to reach this point. This ensures that'the overcenterspring 27 will be substantially fully charged with the maximum amount ofenergy being stored therein before any of its energy is released. Thusthe closing and subsequent opening and resetting operations of thecircuit interrupter will be unaffected in the event control power shouldfail while the movable switch member is closing. By providing adefinite, fixed release point, the blocking means also ensures that asubstantially constant amount of closing energy is always availableeach. time the circuit interrupter is closed and regardless of the speedwith which the operating member 28 is moved to its second position.

The blocking means preferably comprises the same pair of cooperatingblocking elements 67 and 68 described her'einbefore. The blockingelement 68, which is associated with the output end of the toggle, isdisposed for movement along a predetermined arcuate path about pivot 26during closing movement of the switch member 15. With the operatingmember 28 in its first angular position and during most of the movementof this member toward its second position, as clearly indicated in Figs.3 and 4, the blocking element 67 is disposed in this predetermined pathand the element 68 is positively blocked by the lower edge thereof,whereby appreciable switch closing movement of the toggle is prevented.

When the operating member approaches its second position, it passesthrough the position in which it is shown in Fig. 4 (line 29p in Fig. 4representing the path being followed by the laterally extending pin 29carried by the operating member), and it will be observed that thetension spring 27 has moved overcenter with respect to the toggle link33 at this point. As the operating member proceeds beyond this point, itcauses the blunt end of element 67 to move beyond element 68 which willnow be able to travel freely along its predetermined path. In thismanner the blocking means consistently operates near the end of themovement of the operating member toward its second position to free thetoggle and to effect release of energy stored in the spring 27 forproducing switch closing movement of the operating mechanism, whereuponthe closing operation is completed.

As the circuit interrupter operating mechanism is undergoing switchclosing movement, the element 68 moves into its blocking position(Fig. 1) wherein it releasably restrains the operating member 28 in itssecond position. It is important that the electromagnetic means whichhas moved the operating member to its second position remain energizeduntil this blocking action has taken effect, thereby maintaining theoperating member in its second position while the switch closingmovement of the mechanism is getting underway. In order to accomplishthis result, the cutoff switch 72, which controls the energization ofthe solenoid 30, is arranged to be actuated in response to the switchclosing movement of the mechanism. This will ensure that the operatingmember 28 is blocked in its second position and that the spring energyhas been released for imparting irreversible switch closing movement tothe operating mechanism before the solenoid is de-energized.

The cutoif switch 72, as is shown in Figs. 1-3, comprises a resilientswitch arm 74 supporting the electric contact 70 at one end andpivotally connected at its other end to a transverse shaft 75. The shaft75 is suspended between two spaced-apart supporting elements 76 (onlythe near one being shown) fastened to a base member 77, and thecooperating electric contact 71 is mounted on a bracket 78 also fastenedto the base member 77. The base member 77 is located above the operatingmechanism of the circuit interrupter where it is aflixed to the frame11. A broad cantilever control arm 97 is yieldably coupled to the switcharm 74 and depends from the cutoff switch in cooperation with theoperating mechanism for actuating the separable contacts 70 and 71.Suitable spring means is provided for biasing the interconnected switchand control arms 74 and 79 in a counterclockwise direction about theshaft 75 to predetermined normal positions wherein the contact 70 ismaintained in an engaged position with respect to contact 71, as can beseen in Fig. 3.

The control arm 79 of the cutoff switch 72 is disposed for engagement byan upwardly extending appendage 33a of the toggle link 33 in response toswitch closing movement of the operating mechanism. The final stage of aclosing operation involves the straightenng of the toggle withsnap-action, and the toggle link 33 is abruptly pivoted counterclockwiseon pin 36 from the position shown in Fig. 4 to the position shown inFig. 1. As a result, appendage 33a of link 33 engages the control arm 79and tilts this arm in a clockwise direction about shaft 75 to anactuated position, thereby causing separation of the cooperatingcontacts 71) and 71. See Fig. 1. The contact 79 has been moved to adisengaged position thereby opening the energizing circuit for thesolenoid 30 and deenergizing the electromagnetic means. The operatingmember 28, which was being upheld in its second position by the armature31, is now releasably restrained in this position by the abuttingblocking elements 67 and 68, and the armature 31 cannot return to itsoriginal position shown in Fig. 3.

As long as the circuit interrupter is closed, the control arm 79 of thecutoff switch is held in its actuated position, thereby preventingreenergization of the electromagnetic means, by the operating mechanismacting through link 33. The control arm is also disposed for engagementby a protrusion 80 of the guide member 21 in response to switch openingmovement of the operating mechanism, whereby control arm 79 ismaintained in its actuated position, and energization of the solenoid 30is prevented, with the mechanism in its trippedopen position (Fig. 2).Upon operation of the latch 37 with the circuit interrupter closed, theguide member 21 is driven in a clockwfse direction about pivot 22 to itsunlatched position and protrusion 81) moves into engagement with controlarm 79. At the same time the toggle is collapsing and appendage 33a oftoggle link 33 rides along the curved underside arm 79 while holdingthis arm in its actuated position. The operating mechanism is arrangedso that during the initial portion of its switch opening movement theappendage 33a of link 33 is maintaining the control arm '79 in itsactuated position, while during the remaining portion of this movementthe protrusion 88 of guide member 21 will prevent the control arm fromreturning to its normal position, whereby the cooperating electriccontacts 70 and 71 are caused to be separated throughout the openingoperat on.

The cutoff switch 72 will not reset to permit subsequent energization ofthe solenoid 30 until a resetting operation of the mechanism isunderway, as indicated by counterclockwise movement of the guide member21 toward its latched position. Th s ensures that before the solenoidcan again be energized the movable switch member 15 is fully open andthe condition of the operating mechanism and the armature 31 will beproper for a normal closing operation. During the resetting operation,the protrusion 80 of the gu'de member 21 drops away from the control arm79 thereby enabling the control and switch arms 79 and 74 to move totheir normal positions in accordance with their bias, whereupon contact70 engages contact 71 to set up the energizing circuit for the solenoid30 (Fig. 3).

When energized, the solenoid 30 wll produce a magnetic field. Amagnetizable yoke 94 provides physical support for the solenoid andforms a part of the magnetic circuit for its field. The yoke 94comprises a plurality of iron laminations stacked between a set ofhangers 95, and the hangers 95, as can be seen in Figs. 1 and 3, areprovided w'th mounting feet securely fastened by rivets or the like tothe underside of a horizontal channel element 11a of the circuitinterrupter frame member 11. Preferably the yoke is made in two separateparts, the bottom part including supporting elements 96 which arerespectively fastened to the hangers by bolts 97. This enables thehollow spool 98 on which the solenoid coil 99 is wound to beconveniently clamped between the two parts of the yoke 94, as indicatedin the drawings.

The configuration of the yoke 94 is best seen in Fig. 5. Clearly shownin this sectional view are a plurality of rivets 100 by means of whichthe set of hangers 95 and supporting elements 96 are respectivelyattached to edges of the flanges.

the iron laminae comprising the two parts of the yoke 94. The axiallyoutward facing surfaces of the flanges located at opposite ends of thespool 98 are provided with grooves 191 for receiving the transverseportions of the yoke 94. The width of each groove 101 is substantiallythe same as the width of the transverse portions of the yoke, wherebythese portions nest snugly between the sidewalls defining the grooves.The depth of each groove, however, is tapered and is deepest at theouter Therefore the yoke 9 iwill rest against the bottom'of the grooves101 only in the vicinity of the sp'ools hollow body portion 98a, as isseen in Fig. 5. As a result, when the spool 98 is clamped between thetwo parts of the yoke 94, its body @ila is axially compressed while itsflanges are relieved of bend'ng stresses. Since the compression strengthof' electric insulating material, of which the spool is made, is greaterthan the tensile or bending strength of such material, this featureof'ourinvention materially improves the ability of the spool tosuccessfully withstand the mechanical shock to which it is subjectedduring operation of the circuit interrupter.

The loke 94 includes a pole piece 192 which extends into the solenoidspool 98 at its upper end. The transverse dimension of the pole piece162 is substantially the same as the transverse distance between theinner surfaces of the sidewalls of the spool body 98a so that there is asnug fit therebetween, as is shown in Fig. 5. n the other hand, thewidth of the pole piece is less than the corresponding distance betweenthe spool sidewalls, whereby ample passageways are provided on oppositesides of the pole piece, respectively, for a pair of generallylongitudinally movable, spaced-apart elongated metallic strips 103 andres. The strips 163 and 164 comprise part of the armature or plunger 3?.which is disposed in the solenoid 3% for longitudinal movement under theinfluence of the force of magnetic attraction.

A laminated, magnetizable core piece 195 of the plunger 31 is sandwichedbetween the parallel strips 103 and 104, near their lower ends, where itis securely attached by means of recessed-head rivets MP6 or the like.The core piece 1 comprises another portion of the magnetic circuit forthe magnetic field'produced by the solenoid 30 when energized, and, incooperation with the yoke 94, it is disposed for movement into the lowerend of the solenoid spool 93 in accordance with the magnetic forceexerted by the field. For this purpose the laminae comprising the bottompart of the yoke 94 are discontinued immediately beneath the openingthrough the spool 98, and the supporting elements 96' are appropriatelybowed at 95a. The strips 103 and 104 of the plunger 31 extend upwardlythrough the solenoid spo'ol, passing on opposite sides of the core piece192, and are rigidly joined at their upper ends to an armature extensionit which in turn is positively connected by means of the pin 29 to theoperating member 28 of the circuit interrupter operating mechanism.

The rigid junction between the metallic strips M3 and 104 and armatureextension Hi7, best seen in Figs. 5 and 6, is designed for convenientconnection and disconnection. This will enable the plunger 31 to bereadily assembled in, and removed from, the solenoid Edwith thesupporting yoke 94 mounted on the framernember i1 and the armatureextension 1W pinned to the operating member 28 of the mechanism. Thelower end of the armature extension is centrally disposed intermediatethe upper ends of strips 163 and Edd, with the width of N7 correspondingto the Width of the core piece 1&5. As is shown in Figs. 5 and 6, themetallic armature extension is provided with a set of laterallyprotruding lugs or ears 1% which are releasably keyed into cooperatingslots in the strips 163 and 1%. A fiat-head screw 1tl"inserted through atapered hole 11b inthe upper end of strip 103 is threaded into a tappedhole 11 in strip 134 in order to interconnect these corresponding endsof the strips and keep them from being spread apart. In this maner arigid and strong junction is provided.

7 For the purpose of connecting and disconnecting the armature extensionHi7 and the metallic strips, a tapped hole 112 is provided in strip 1&3abovethe' hole 110. The screw 1'fi9 when removed from itsinterconnecting disposition and turned into the hole 112, as is shown at109 in Fig. 6', will abut a solid portion of the strip 104 and forcethis strip apart from strip 1'93 to a relative position such as thatindicated at lit i, whereby the lugs 108 of the armature extension arereleased from the cooperating slots in the strips and the armatureextension 107 can be easily removed.

pon" energization of the solenoid coil 9?, the core pieceliiS ofarmature 31 is moved by the force of magnetic attraction in a generallylongitudinal direction from a lower or normal position shown in Fig. 3to an attracted position at the upper limit of its longitudinalmovement, shown in'Fig. l. The magnetic force is transmitted by way ofthe armature extension 107 to the operating mechanism whose member 23 isthereby driven from its first or reset position to its second oroperated position, and as a result the circuit interrupter is closed.The operating member 23 is stopped in its second position, beyond whichit cannot be moved, by the abrupt interengagement withinthe sloenoid 39of the core piece of armature 31 and the pole piece of yoke 94 occurringwhen the armature attains its attracted position. See Fig. 5. This isthe stop means for the operating member referred to hereinbefore. Theforce of gravity assists in returning the armature 31 to its normalposition during the previously described resetting operation of themechanism, and the normal. position of the armature is determined by theinterengagement of the bottom edge liiia of the armature 137 withthe topof yoke 94.

The upper end of the armature extension 197, being positiveiy'pinned tothe pivotally mounted operating member 22' of the mechanism, follows anar uate path (29p in Fig; 3) as the operating member is moving betweenits first and second angular positions. In accordance with ourinvention, the elongated armature or plunger 31 of the electromagneticmeans is guided in a manner to permit lateral deviation thereof whileits upper end is moving along this arcuate path, whereby no additionalpivotally connected link or joint is needed for connecting the plungerto the operating'member. As is clearly shown in Pig. 3, the width of theopening between the sidewalls of the'body 93a of thesolenoidspool ismade slightly greater than the corresponding dimension of the plungerfiityan'd consequently the plunger fits sloppily or loosely in thespool; Thus the plunger is guided with leeway for a relatively smallamount oflateral or sidewise deviation during its generally longitudinalmovement in the solenoid. In other words, the plunger is able to deviatefrom-straight-line motion while'driving the pivotal-lymovable operatingmember 2% toward its second position upon energization of the solenoid,such lateral deviation by the plunger being the result of its upper endfollowing an arcuate path. This deviation is minimized by supportingthesolenoid and plunger in tlited disposition as shown.

By using the-spool 98 itself for supporting and guiding" the plunger 31in accordance with the preferred construction and arrangement shown inFigs. 3'and 5, frictional forces and Wear on the relatively movableparts'are materially reduced. The spool 98 is made of moldedelectricinsulating material which provides a good wear-resistant surfacefor the sliding motion of the plunger, and the plunger does not bearagainst any'metallic parts. This arrangement is relatively simple andinexensive to fabricate and asemble, and no separate guides arerequired.

As the plunger 31 moves toward its attracted position and consequentlydrives the operating member 28 toward its second position,theoverc'enter tension spring-27 of the mechanism is stretched orcharged. The force required to stress the spring 28, which has aconventional spring constant, increases linearly with its displacement.The magnetic force exerted on a moving plunger in the field of asolenoid will conventionally increase nonlinearly with its displacement.Preferably the force-displacement characteristic of the plunger 31should approximately match that of the spring 27 being charged thereby,and toward this desired end we have designed the electromagnetic meansso as to reduce the non-linearity of the rate of increase of themagnetic force experienced by the plunger 31 while moving toward itsattracted position.

In the embodiment of our invention illustrated in Fig. 5, the face ofthe pole piece 102 is recessed and the cooperating face of the corepiece 105 is tapered. The tapered face of 105 is received in therecessed face of 102 when the plunger 31 is in its attracted position asshown. The purpose of this particular configuration and arrangement ofthe cooperating pole and core pieces is to produce an accelerated rateof decrease of the reluctance of the magnetic circuit, by acceleratingthe reduction of the effective air gap between the pole and core faces,as the plunger 31 is travelling through the intermediate phase of itslongitudinal movement toward its attracted position, whereby the plungerexperiences an increasing force of attraction throughout this phase ofits movement. As a result, the magnetic force impelling the plunger 31from its normal to its attracted position will increase at a relativelylinear rate, i.e., the magnetic force bears a generally linearrelationship to the distance moved by the plunger under the influence ofthis force. Without this feature of our invention, the magnetic forceexerted on the plunger would be substantially constant during asignificant portion of its longitudinal movement.

Having described in detail the circuit interrupter structure illustratedin Figs. 1-6, its mode of operation will now be summarized. With thecircuit interrupter switch member 15 in an open circuit position and theoperating mechanism in its reset condition, as is shown in Fig. 3, thecontacts 70 and 71 of the cutoff switch 72 are in engagement and aclosing operation may be initiated by operating a suitable externalcontrol switch to energize the solenoid 30. The plunger 31 is raisedfrom its normal position by the resulting force of magnetic attraction,and the operating member 28 is driven in a clockwise direction about itspivot 22 toward its operated position. This stretches the tension spring27 which consequently accumulates closing, tripping and resettingenergy. The spring is carried overcenter with respect to the toggle link33 of the mechanism, and a closing force is exerted on the toggle.

During this portion of the closing operation the toggle is substantiallyimmovable, and consequently the switch member 15 cannot be moved to itsclosed circuit position, because the toggle link 33 is being heldstationary by the guide member 21 which is releasably restrained in itslatched position by the latch 37, and the toggle link 34 is being heldstationary by the blocking action of elements 67 and 68 which preventappreciable clockwise movement of the output crank 25 to which the link34 is pinned. As the operating member 28 approaches its operatedposition, it reaches a point just beyond the position in which it isshown in Fig. 4 and the blocking element 67 is moved out of engagementwith the element 68. The output crank 25 is now free to move clockwiseabout its pivot 26, and the spring 27 immediately releases stored energyas snap-action switch closing movement is imparted to the operatingmechanism.

Early during this switch closing movement of the mechanism, the blockingmeans 67, 68 becomes effective to prevent the return of the operatingmember 28 toward its reset position. The solenoid 30 will remainenergized, thereby upholding the operating member in its operatedposition, until the separable contacts 70 and 71 of the cutoff switchare actuated by the control arm 79 upon engagement thereof by appendage33a of the operating mechanism during the final stage of its switchclosing movement. See Fig. 1.

To initiate an opening operation, the trip shaft 40 is rotatedcounterclockwise from its normal position thereby removing the prop 41from roller 46. As a result, the latch 37 releases the guide member 21which is forthwith driven in a clockwise direction about its pivot 22 bythe action of the tension spring 27. This enables the spring to releaseopening energy, and the mechanism undergoes switch opening movementthereby pulling the switch member 15 to its open circuit position shownin Fig. 2. As the guide member is moving to its unlatched position, thetoggle link 33 moves through the centerline of the spring 27 at whichpoint snap-action collapse of the toggle takes place.

During the course of the switch opening movement of the operatingmechanism, the concave camming surface 56 of the guide member 21 engagesroller 57 of the toggle and controls the movement thereof, whereby asubstantially uniform rate of energy release by the spring 27 isobtained throughout the opening operation. At the conclusion of theopening operation, the blocking element 68 has moved out of engagementwith the cooperating element 67, thereby releasing the operating member28 for return to its reset position, and the cutoff switch 72 remainsactuated due to the engagement of its control arm 79 by protrusion 80 ofthe guide member 21 when in its unlatched position. See Fig. 2.

The operating mechanism, in this embodiment of the invention,automatically undergoes a resetting operation immediately following theabove-described opening operation. The force of spring 27 applied to theoperating member 28 tends to move this member in a counterclockwisedirection toward its reset position, and by means of pin 29 acting onthe guide member arm 65, the guide member 21 is simultaneously propelledin a counterclockwise direction toward its latched position. This causesthe toggle knee 35 to follow a path which progressively converges withthe path 29 of pin 29, thereby enabling the spring 27 to give up stillmore energy for effecting the resetting operation.

When the guide member 21 reaches its latched position, the latch 37 isautomatically reset by the action of its biasing spring 47 which tiltsthe intermediate latch member 42 clockwise so that its stud 44 engagesthe heel of the guide member leg 45, whereupon the trip shaft 40 returnsto its normal position. See Fig. 3. The cutoff switch 72 is now reset,the operating member 28 is in its reset position, and the plunger 31 hasreturned to its normal position in readiness for another closingoperation.

Referring now to Figs. 79, a manually operable embodiment of theinvention has been illustrated and will now be described. Thisembodiment is essentially the same as that described hcreinbefore, andthe same reference characters have been used in these three figures toidentify the various parts thereof that are identical to the parts shownin Figs. 1, 3 and 4, respectively.

The operating member of the manually operable mechanism, as can be seenin Fig. 7, is pivotally pinned at 116 to the circuit interrupter framemember 11, instead of being mounted on the rod 22 as was the case withthe operating member 28 previously described. The operating member 115,which preferably is a generally U-shaped member comprising twoupstanding parts (only thesfar one being shown) rigidly interconnectedby a single transverse part 115a, is pivotally movable from a first orreset position shown in Fig. 8 to a second or operated position shown inFig. 7, and it carries the laterally extending pin 29 along apredetermined arcuate path 29r.

With the circuit interrupter closed, as is shown in Fig. 7, theoperating member 115 is positively blocked in its second position bymeans including, in this embodiment of the invention, a blocking member117 pivotally supported on the rod 22. The blocking member 117preferably comprises two identical upstanding parts, only the far onebeing shown, rigidly interconnected by a transverse part 117a, and thismember is disposed for engagement by and movement with the operatingmember 115. Counterclockwise movement of the operating member 115 aboutits pivot 116 from its second to its first position must be accompaniedby counterclockwise movement of the blocking member 117 about its pivot22, due to the abutting engagement 'of a tail 118 of the operatingmember with a cooperating surface 119 of the blocking member.Counterclockwise movement of the blocking member 117, however, isprevented whenever the switch member of the circuit interrupter isclosed due to the blocking element or lug 68' of the output crank 25being disposed in interfering relationship with the blunt end of acooperating element 120 protruding integrally from member 117. See Fig.7.

The only way in which the circuit interrupter can be opened is byoperating the latch 37 to release the guide member 21, whereupon the'overcenter spring 27 effects switch opening movement of the operatingmechanlsm. During the opening operation, the output crank 25 is pivotedcounterclockwise to the position shown in Fig. 8 and the blockingelement 68 is moved out of its blocking disposition in relation to theelement 120. This releases the blocking member 117 which is now free tomove pivotally in a counterclockwise direction. Consequently theoperating member 115 is no longer restrained in Its second position andcan be returned at any time to its first position, thereby resetting theoperating mechanism and the latch in the manner described hereinbeforein connection with Figs. 1-3. However, in the manually operableembodiment of the invention, the resetting operation is effectedmanually.

In order to move the operating member 115 between its first and secondpredetermined positions, a manually operable handle mechanism isprovided. This mechanism includes a shaft 121 which is journaled in astationary escutcheon plate 122 affixed to the frame 11, and thepistol-grip operating handle 32 is attached to the outer end of theshaft 121 for effecting limited rotatron thereof. Anchored to the innerend of the shaft 131 is a crank 123 having an axially extending crankpin124. A tie bar 125 positively couples the crankpin 124 to the pin 29carried by the operating member 115. A tension spring 126 iseccentrically connected to the crank 1 23 in a manner to bias the handle32 in a clockwise dlrection, as viewed from the front of the circuitinterrupter, to' a substantially vertical position in which it is shownin Fig. 7.

With the circuit interrupter open, the operating handle 32 can bemanually rotated in a counterclockwise direction to the position shownin Fig. 8. This impels the tie bar 125 downwardly and moves theoperating member 115 in a counterclockwise direction to its firstposition thereby resetting the mechanism and partially stressing orcharging the overcenter spring 27. The blocking member 117 issimultaneously pivoted in a counterclockwise direction to the positionshown in Fig. 8, and the lower edge of its protrusion 120is now disposedin V blocking relationship with the element 680i the output crank 25.Thus the output crank 25 is prevented from undergoing appreciableclockwise pivotal movement, and as a result both the operating mechanismand the movable switch member of the circuit interrupter are positivelyrestrained in their open positions.

Subsequent clockwise rotation of the handle 32 drives the operatingmember 115 in a clockwise direction about its pivot 116 from its firstposition (shown in Fig. 8) toward its second position. This actionfurther charges the'spring' 27 which moves overcenter with respect tothe toggle link 33 and exerts. a switch closing force on the toggle. Dueto the abutting engagement between a finger 127 of the blocking member117 and a cooperating edge 128 of the operating member 115, clockwisemovement of the operating member to its second position necessarilyactuates the blocking member in a clockwise direction about its pivot22.

As the operating member approaches its second position and the spring 27is substantially fully charged, the pin 29 of member 115 passes throughthe point at which it is shown in Fig. 9, whereupon the element of theblocking member 117 is moved out of its blocking disposition in relationto the cooperating element 68 and the output crank 25 is freed forclockwise movement. In this manner the blocking means is renderedineffective, and the operating mechanism is now able to undergosnap-action switch closing movement in accordance with the force beingexerted by the spring 27, thereby closing the circuit interrupter. Byproviding a predetermined release point near the end of the clockwisemovement of the operating member 115, the blocking means ensures thatthe same amount of closing energy will be given up by the overcenterspring 27 every time the interrupter is closed regardless of the speedwith which the handle 32 is operated,

The second position of the operating member 115 is determined by theinterengagement between the transverse part 115a of this member and therod 55 which is rigidly affixed to the frame 11, as is shown in Fig. 7.This stops further clockwise movement of the operating member about itspivot 116. With the circuit interrupter closed, counterclockwisemovement of the operating member is prevented by the blocking means117-20 and 68 described above.

The operation of the manually operable mechanism illustrated in Figs.79, except for the particulars pointed out above, is the same as that ofthe electrically operable mechanism already described.

While we have shown and described preferred forms of our invention byway of illustration, many modifications will occur to those skilled inthe art. We therefore contemplate by the claims which conclude thisspecification to cover all such modifications as fall within the truespirit and scope of our invention.

What we claim as new and desire to secure by Letter Patent of the UnitedStates is:

1. A circuit interrupter comprising: a frame member; a movable switchmember pivotally supported by the frame member; a toggle having one endconnected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; anoperating member mounted on said frame for pivotal movement; means formoving the operating member from first to second predeterminedpositions; an overcenter spring interconnecting the operating member andthe toggle and effective in response to movement of the operating memberfrom its first to its second position to produce snap-action switchclosing movement of the toggle; means eifective during closing operationand subsequent thereto for positively preventing movement of theoperating member from its second to its first position; and meansresponsive to toggle releasing operation of the latching means foreffecting switch opening movement of the toggle; said means forpreventing movement of the operating member being disposed .to permitmovement of the operating member to its first the operating member fromits first to its second position to produce snap-action switch closingmovement of the toggle; and blocking means disposed to releasablyrestrain the operating member in its second position with the switchmember closed; said overcenter spring being effective in response totoggle releasing operation of the latching means to produce switchopening movement of the toggle and said blocking means being arranged tofree the operating member for return to its first position in responseto the opening operation.

3. In a circuit interrupter: a movable switch member; a toggle havingone end connected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; a movableoperating member; an overcenter spring interconnecting the operatingmember and the toggle and effective in response to movement of theoperating member from a first position to a second position to producesnap-action switch closing movement of the toggle; and blocking meansdisposed for movement in accordance with the movement of said one end ofthe toggle for releasably restraining the operating member in saidsecond position; said overcenter spring being effective in response totoggle releasing operation of the latching means to produce switchopening movement of the toggle as a consequence of which said blockingmeans is moved to free the operating member for return to said firstposition.

4. In a circuit interrupter: a switch member movable between open andclosed circuit positions; a toggle hav ing one end connected to theswitch member; latching means for releasably restraining the other endof the toggle in a latched position; an operating member supported forpivotal movement between first and second positions; an overcenterspring interconnecting the operating member and the toggle and effectivein response to movement of the operating member from its first to itssecond position to produce snap-action switch closing movement of thetoggle, whereby the switch member is moved to its closed circuitposition; and means actuated in response to movement of the switchmember to its closed circuit position for blocking the operating memberin its second position until the switch member returns to its opencircuit position.

5. A circuit interrupter comprising: a frame member; a switch membersupported by the frame member for movement between closed and opencircuit positions; a toggle having one end connected to the switchmember; a guide member connected to the other end of the toggle andsupported by the frame for movement between latched and unlatchedpositions; a latch disposed releasably to restrain said guide in itslatched position; an operating member pivotally mounted on the frame;means for moving the operating member from a first position to a secondposition; an overcenter tension spring interconnecting the operatingmember and the toggle and efiective in response to movement of theoperating member from its first to its second position to producesnapaction switch closing movement of the toggle; a first blockingelement integrally associated with the operating member and movablealong a predetermined path in accordance with movement of the operatingmember between its first and second positions and a second blockingelement, responsive to movement of the switch member, disposed formovement into the predetermined path of movement of the first blockingelement during closing operation thereby to block the operating memberin its second position; said overcenter spring being effective inresponse to guide releasing operation of the latch to drive the guide toits unlatched position and produce switch opening movement of thetoggle; said second blocking element being disposed for movement out ofsaid predetermined path during opening operation thereby unblocking theoperating member and permitting its return to its first position.

6. An electric circuit interrupter comprising: a frame member; a movableswitch member pivotally supported by the frame member in cooperationwith a relatively stationary switch member for closing and opening theelectric circuit; a toggle having one end connected to the movableswitch member; latching means for releasably restraining the other endof the toggle in a latched posi tion; an operating member pivotallymounted on the frame for movement between first and second positions; anovercenter tension spring interconnecting the operating member and thetoggle and effective in response to movement of the operating memberfrom its first to its second position to produce snap-action switchclosing movement of the toggle; a blocking member pivotally supported bythe frame for engagement by and movement with the operating member; andmeans for preventing movement of the blocking member whenever thecircuit interrupter is closed thereby blocking the operating member inits second position; said overcenter spring being effective in responseto toggle releasing operation of the latching means to produce switchopening movement of the toggle; said blocking member being released formovement whenever the circuit interrupter is opened.

7. In a circuit interrupter: a frame member; a movaole switch memberpivotally supported by the frame member; a toggle having one endconnected to the switch member; latching means comprising a guide memberconnected to the other end of the toggle and mounted on said frame forpivotal movement between latched and unlatched positions, a trip shaftsupported by said frame for rotation between normal and trippedpositions, and a latch member pivotally mounted on said frame anddisposed intermediate the guide member and a radially protruding portionof the trip shaft for releasably restraining the guide member in itslatched position with the trip shaft in its normal position, saidintermediate latch member and said protruding portion being constructedand arranged so that the resultant force of action and reactiontherebetween is directed normal to the axis of rotation of the tripshaft; an operating member mounted on said frame for pivotal movementbetween first and second positions; an overcenter spring interconnectingthe operating member and the toggle and effective in response tomovement of the operating member from its first to its second positionto produce snap-action switch closing movement of the toggle; andblocking means effective during closing operation and subsequent theretofor positively preventing movement of the operating member from itssecond to its first position; said overcenter spring being effective inresponse to movement of the trip shaft to its tripped position and theresulting release of the guide member to drive the guide member to itsunlatched position and produce switch opening movement of the toggle;said blocking means being disposed to permit movement of the operatingmember to its first position in response to opening operation.

8. A circuit interrupter comprising: a movable switch member; a togglehaving one end connected to the switch member; a guide member supportedfor movement between latched and unlatched positions connected to theother end of the toggle; a latch disposed releasably to restrain theguide member in its latched position; a movable operating member; meansfor moving the operating member from first to second predeterminedpositions; an overcenter spring interconnecting the operating member andthe toggle and effective in response to movement of the operating memberfrom its first to its second position to produce snap-action switchclosing movement of the toggle; means effective during closing operationand subsequent thereto for positively preventing movement of theoperating member from its second to its first position; said overcenterspring being effective in response to guide releasing operation of thelatch to drive the guide member to its unlatched position and producesnap-action switch opening movement of the toggle; and means disposed incooperation with the toggle and effective while the guide member ismoving toward its unlatched position to control the resulting movementof the toggle in a manner to obtain a substantially uniform rate ofenergy release by the overcenter spring throughout the openingoperation; said means for preventing movement of the operating memberbeing disposed to permit movement of the operating'membe'r to its firstposition only after said snap-action switch opening movement of thetoggle has been initiated.

9. in a circuit interrupter: a switch member movable between open andclosed circuit positions; a toggle having one end connected to theswitch member; latching means comprising a guide member movable betweenlatched and unlatched positions connected to the other end of thetoggle; a pivotally mounted latch member biased into self-releasingengagement with the guide member when in its latched position, and atrip member abutting the latch member for holding the latch member inengagement with the guide member thereby to maintain the guide member inits latched position, said trip member being mounted for pivotalmovement with respect to an axis of rotation and being disposed inrelation to said latch member so that the line of action of theresultant force at the abutting surfaces of these two members intersectssaid axis; an operating member movable between first and secondpositions; an overcenter spring interconnecting the operating member andthe toggle for exerting a switch closing force on the toggle as theoperating member moves toward its second position; and blocking meansdisposed in cooperation with the operating and switch members to preventmovement of the switch member to its closed position until the operatingmember approaches its second position, whereupon the blocking means isrendered ineffective to prevent movement of the switch member and thetoggle undergoes snap-action switch closing movement in accordance withthe force exerted by the overcenter spring, and to prevent movement ofthe operating member from its second to its first position whenever theswitch member is in its closed position; said overcenter spring beingeffective, upon pivotal movement of said trip member to release saidguide member, to drive the guide member to its unlatched position andproduce switch opening movement of the toggle; said blocking means beingdisposed to permit movement of the operating member to its firstposition whenever the switch member is in its open position.

10. In a circuit interrupter: a switch member movable between open andclosed circuit positions; a toggle having one end connected to theswitch member; latching means for releasably restraining the other endof the toggle in a latched position; an operating member movable betweenfirst and second predetermined positions; an overcenter springinterconnecting the operating member and the toggle for exerting aswitch closing force at the toggle during movement of the operatingmember toward its second position; and blocking means disposed incooperation with the operating and switch members to prevent movement ofthe switch member to its closed position until the operating memberreaches a predetermined point near its second position, whereupon theblocking means is rendered inefiective to prevent movement by the switchmember and the toggle is able to undergo snap-action switch closingmovement in accordance with the force being exerted by the overcenterspring, and to prevent movement of the operating member from its secondto its first position until the switch member returns to its openposition upon subsequent toggle releasing operation of the latchingmeans.

11. In a circuit interrupter: a switch member movable between open andclosed circuit positions; a toggle having one end connected to theswitch member; latching means for releasably restraining the other endof the toggle in a latched position; an operating member movable betweenfirst and second positions at opposite ends of its normal range ofmovement; an overcenter spring interconnecting the operating member andthe toggle to exert a switch closing force on said toggle duringmovement of the operating member from its first position toward itssecond position; and blocking means effective during said operatingmember movement to prevent movement of the switch member to its closedposition until the operating member reaches a point near its secendposition, whereupon the blocking means is rendered ineffective toprevent movement by the switch member and the toggle is able to undergosnap-action switch closing movement in accordance with the force exertedby the overcenter spring.

12. In a circuit interrupter: a frame member; a movable switch memberpivot'ally supported by the irame member; a togge having one endconnected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; anoperating member mounted on the name for pivotal movement; means formoving the operating member from first to second predeterminedpositions; an overcenter spring interconnecting the operating member andthe toggle and efiective in response to movement of the operating membertoward its second position to exert a switch closing force on thetoggle; and blocking means disposed in cooperation with the operatingmember for releasably restraining the switch member in an open circuitposition while the operating member is moving toward its secondposition, said blocking means being operable as the operating memberapproaches its second position to release the switch member and permitsnap action switch closing movement of the toggle in accordance with theforce exerted by the overcenter spring.

'13. A circuit interrupter comprising: a switch member disposed formovement between open and closed circuit positions; a toggle having oneend connected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; anoperating member disposed for movement between first and secondpositions; an overcenter spring interconnecting the ope-rating memberand the toggle and effective during movement of the operating memberfrom its first position toward its second position to exert a switchclosing force on the toggle; and blocking means disposed for movement inaccordance with the movement of the operating member for preventingappreciable movement or the switch member toward its closed positionuntil the operating member reaches a predetermined point near its secondposition, whereupon said biocking means is moved to a position whereinit is ineffective to prevent movement of the switch member and thetoggle is able to undergo snap-action switch closing movement inaccordance with the force exerted by the overcenter spring.

14. In a circuit interrupter: a switch member mov able between open andclosed circuit positions; a toggle having one end connected to theswitch member; a guide member, connected to the other end of the toggle,movable between latched and unlatched positions; a latch disposedreleasably to restrain -said guide in its latched position; a movableoperating member; means for moving the operating member between firstand second positions; an overcenter spring interconnecting the operatingmember and the toggle for exerting a switch closing force on the toggleas the operating member is moved toward its second position; and meansactuated in response to said operating member movement to block switchclosing movement of the toggle until the operating member approachingits second position, whereupon the toggte is freed for snap-actionswitch closing movement in accordance with the force exerted by theovercenter spring; said overcenter spring being effective in response toguide releasing operation of the latch to drive 'the guide to its 21unlatched position and produce switch opening movement of the toggle.

15. A circuit interrupter comprising: a frame member; a switch membermovably supported by the frame member; a toggle having one end connectedto the switch member for moving the switch member between closed andopen circuit positions; a first blocking element associated with saidone end of the toggle and movable along a predetermined path inaccordance with the movement of said one end; latching means forreleasably restraining the other end of the toggle in a latchedposition; an operating member pivotally mounted on the frame; means formoving the operating member from a first position to a second position;an overcenter tension spring interconnecting the operating member andthe toggle for exerting a switch closing force on the toggle as theoperating member is moved toward its second position; and a secondblocking element disposed in the predetermined path of movement of thefirst blocking element for preventing appreciable movement of said oneend of the toggle, whereby the toggle is unable to move the switchmember to its closed circuit position, said second blocking elementbeing moved out of said predetermined path in response to the operatingmember approaching its second position thereby unblocking said one endand releasing the toggle for snap-action switch closing movement inaccordance with the force exerted by the overcenter spring.

16. An electric circuit interrupter comprising: a frame member; amovable switch member pivotally supported by the frame member incooperation with a relatively stationary switch member for closing andopening the electric circuit; a toggle having one end connected to themovable switch member; latching means for releasably restraining theother end of the toggle in a latched position; an operating memberpivotally mounted on the frame for movement between first and secondpositions; an overcenter tension spring interconnecting the operatingmember and the toggle and eifective during move ment of the operatingmember toward its second position to exert a switch closing force on thetoggle; and a blocking member pivotally supported by the frame forengagement by and movement with the operating member, said blockingmember being disposed to restrain movement of the toggle thereby toprevent closing of the circuit interrupter until the operating memberhas been moved to a predetermined point near its second position atwhich point the blocking member releases the toggle for snap-actionswitch closing movement in accordance with the force being exerted bythe overcenter spring.

17. A circuit interrupter comprising: a frame member; a movable switchmember pivotally supported by the frame member; a toggle having one endconnected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; anoperating member mounted on said frame for pivotal movement;electromagnetic means for moving the operating member from first tosecond predetermined positions, said electromagnetic means including asolenoid for producing a magnetic field when energized, means disposedto support the solenoid, and a rigid, elongated magnetizable armature,comprising a portion of the magnetic circuit for said field, disposedfor longitudinal movement in accordance with magnetic force exerted bysaid field, said armature being connected to the operating member andbeing guided in a manner permitting lateral deviation thereof whilemoving the operating member toward its second position upon energizationof the solenoid; an overcenter spring interconnecting the operatingmember and the toggle and effective in response to movement of theoperating member from its first to its second position to producesnap-action switch closing movement of the toggle; means effectiveduring closing operation and subsequent thereto for preventing movementof the operating member from its second to its first position; and means22 responsive to toggle releasing operation of the latching means foreffecting switch opening movement of the toggle; said means forpreventing movement of the operating member being disposed to permitmovement of the operating member to its first position in response toopening operation.

18. In a circuit interrupter: a frame member; a movable switch memberpivotally supported by the frame member; a toggle having one endconnected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; anoperating member mounted on the frame for pivotal movement;electromagnetic means for moving the operating member from first tosecond predetermined positions, said electromagnetic means including asolenoid for producing a magnetic field when energized, a magnetizableyoke comprising a portion of the magnetic circuit for said field, and arigid, elongated magnetizable armature, comprising another portion ofthe magnetic circuit, disposed for longitudinal movement in accordancewith magnetic force exerted by said field, said armature being connectedto the operating member and being guided in a manner enabling thearmature to deviate laterally while moving the operating member towardits second position upon energization of the solenoid; an overcenterspring interconnecting the operating member and the toggle and effectivein response to movement of the operating member toward its secondposition to exert a switch closing force on the toggle; and blockingmeans disposed in cooperation with the operating member for releasablyrestraining the switch member in an open circuit position while theoperating member is moving toward its second position, said blockingmeans being operable as the operating member approaches its secondposition to release the switch member and permit snap-action switchclosing movement of the toggle in accordance with the force exerted bythe overcenter spring.

19. In a circuit interrupter: a movable switch member; a toggle havingone end connected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; anoperating member disposed for pivotal movement from a first angularposition to a second angular position; electromagnetic means for movingthe operating member comprising a solenoid for producing a magneticfield when energized, a magnetizable yoke comprising a portion of themagnetic circuit for said field, and a rigid magnetizable armature,comprising another portion of the magnetic circuit, disposed formovement in accordance with magnetic force exerted by said field, saidarmature being connected to the operating member and being guided in amanner enabling the armature to deviate laterally while moving theoperating member toward its second angular position upon energization ofthe solenoid; and an overcenter spring interconnecting the operatingmember and the toggle and effective in response to movement of theoperating member to its second angular position to produce snap-actionswitch closing movement of the toggle.

20. A circuit interrupter comprising: a frame member; a movable switchmember pivotally supported by the frame member; a toggle having one endconnected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; anoperating member mounted on said frame for pivotal movement;electromagnetic means for moving the operating member from first tosecond predetermined positions, said electromagnetic means including asolenoid for producing a magnetic field when energized, a magnetizableyoke mounted on said frame and disposed to support the solenoid, a rigidmagnetizable plunger disposed for longitudinal movement within thesolenoid in accordance with the magnetic force of said field, one end ofthe plunger being connected to the operating member at a point whichfollows an arcuate path as the operating member is moved pivotallytoward its second position upon energization of the solenoid, and meansguiding the plunger with leeway for lateral deviation thereof as saidone end moves along said arcuate path; an overcenter springinterconnecting the operating memher and the toggle and eifective inresponse to movement of the operating member from its first to itssecond position to produce snap-action switch closing movement of thetoggle; means effective during closing operation and subsequent theretofor positively preventing movement of the operating member from itssecond to its first position; and means responsive to toggle releasingoperation of the latching means for effecting switch opening movement ofthe toggle; said means for preventing movement of the operating memberbeing disposed to permit movement of the operating member to its firstposition in response to opening operation.

21. In a circuit interrupter: a frame member; a movable switch memberpivotally supported by the frame member; a toggle having one endconnected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; anoperating member mounted on the frame for pivotal movement;electromagnetic means for moving the operating member from first tosecond predetermined positions, said electromagnetic means including asolenoid for producing a magnetic field when energized, a magnetizableyoke mounted on the frame and disposed to support the solenoid, a rigidmagnetizable plunger disposed for longitudinal movement within thesolenoid in accordance with the magnetic force of said field, one end ofthe plunger being connected to the operating member at a point whichfollows an arcuate path as the operating member is moved pivotallytoward its second position upon energization of the solenoid, and meansfor relatively loosely guiding the plunger thereby permitting lateraldeviation thereof as said one end moves along said arcuate path; anovercenter spring interconnecting the operating member and the toggleand effective in response to movement of the operating member toward itssecond position to exert a switch closing force on the toggle; andblocking means disposed in cooperation with the operating member forreleasably restraining the switch member in an open circuit positionwhile the operating member is moving toward its second position, saidblocking means being operable as the operating member approaches itssecond position to release the switch member and permit snapactionswitch closing movement of the toggle in accordance with the forceexerted by the overcenter spring.

22. In a circuit interrupter: a movable switch member; a releasablylatched operating mechanism connected to the switch member, saidmechanism including a spring arranged to release stored energy forimparting switch closing movement to the mechanism; a movable operatingmember connected to the spring and disposed for pivotal movement from afirst angular position to a second angular position to control theaccumulation of energy by the spring; and electromagnetic means formoving the operating member comprising an electric coil wound on a spoolof electric insulating material for producing a magnetic field whenenergized, means disposed to support the spool, and a magnetizableplunger disposed for movement within the spool in a generallylongitudinal direction under the influence of the force of magneticattraction, said plunger being connected to the operating member formoving the operating member to its second angular position uponenergization of said coil and being guided by the spool with leeway forlateral deviation while moving the operating member toward said secondposition.

23. In a circuit interrupter: a movable switch mem her; a releasablylatched mechanism connecting to the switch member for controlling themovement thereof; a pivotally movable operating member coupled to themechanism and movable from first to second predetermined positions tocause switch closing movement of the mechanism; and electromagneticmeans for moving the operating member to its second position comprisinga solenoid for producing a magnetic field 'when energized, meansdisposed to support the solenoid, a rigid, elongated magnetizablearmature, providing a portion of the magnetic circuit for said field,positively'connected tothe operating member and disposed forlongitudinal movement in accordance with magnetic force exerted by saidfield, and means guiding the armature with leeway for lateral deviationthereof While moving the operating member toward its second positionupon energization of the solenoid.

24. In electromagnetic apparatus for moving a pivotally mountedoperating member'from a'first angular :position to'asecond angularposition; a solenoid comprising an electric coil wound on a spool ofelectric insulating material for producing a magnetic field whenenergized; a magnetizable yoke disposed to support the spool; and arigid magnetizable plunger disposed within the spool and guided therebywith leeway fora relatively small amount of lateral deviation as theplunger is moved in a generally longitudinal direction by the force ofmagnetic attraction, one end of the plunger being connected 'to theoperating member at a point which follows an arcuate path while theplunger is moving the operating member toward its second angularposition upon energization of the coil.

25. In electromagnetic apparatus for moving a pivotally mountedoperating member from a first angular position to a second angularposition: a solenoid comprising an electric coil wound on a spool ofelectric insulating material for producing a magnetic field whenenergized; a magnetizable yoke arranged to support the spool; and arigid magnetizable plunger disposed within the spool for longitudinalmovement in accordance with the force of magnetic attraction; saidplunger being connected to the operating member for movement thereofupon energization of the solenoid and said spool being constructed andarranged for relatively loosely guiding the plunger thereby enabling theplunger to deviate laterally while moving the operating member towardits second angular position.

26. In electromagnetic apparatus for moving a'pivotally movableoperating member from a first position to a second position: a solenoidfor producing a magnetic field when energized; means disposed to supportthe solenoid; a rigid, elongated magnetizable Jarmature, comprising aportion of the magnetic circuit for 'said field, positively coupled tothe operating member and disposed for longitudinal movement inaccordance with 'magnetic force exerted by said field; and means guidingthe armature with leeway for lateral deviation thereof while moving theoperating member toward its second position upon energization of thesolenoid.

27. A circuit interrupter comprising: a frame member; a movable switchmember pivotally supported by the frame member; a toggle having one endconnected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; anoperating member mounted on said frame for pivotal movement;electromagnetic means for moving the operating member from first tosecond predetermined positicns, said electromagnetic means comprising asolenoid for producing a magnetic field when energized, a magnetizableyoke for the solenoid having a pole piece extending into one endthereof, and a magnetizable plunger disposed for longitudinal movementwithin the solenoid in accordance with magnetic force exerted bysaidfield, said plunger being connected to the operating member andincluding a core piece disposed to engage said pole piece at the limitof said longitudinal movement, said pole and core pieces beingconfigured and arranged so that the plunger experiences substantiallylinearly increasing mag: netic force while moving the operating membertoward its 25 second position upon energization of the solenoid; anovercenter spring interconnecting the operating member and the toggleand effective in response to movement of the operating member from itsfirst to its second position to produce snap-action switch closingmovement of the toggle; means effective during closing operation andsubsequent thereto for positively preventing movement of the operatingmember from its second to its first position; and means responsive totoggle releasing operation of the latching means for effecting switchopening movement of the toggle; said means for preventing movement ofthe operating member being disposed to permit movement of the operatingmember to its first position in response to opening operation.

28. In a circuit interrupter: a frame member; a movable switch memberpivotally supported by the frame member; a toggle having one endconnected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; anoperating member mounted on the frame for pivotal movement;electromagnetic means for moving the operating member from first tosecond predetermined positions, said electromagnetic means comprising asolenoid for producing a magnetic field when energized, a magnetizableyoke disposed to provide a portion of the magnetic circuit for saidfield and provided with a pole piece extending into one end of thesolenoid, and a magnetizable plunger disposed for longitudinal movementwithin the solenoid in accordance with magnetic force exerted by saidfield, said plunger being connected to the operating member andincluding a core piece disposed to engage said pole piece at the limitof said longitudinal movement, said pole and core pieces beingconfigured and arranged to reduce the non-linearity of the increasingmagnetic force experienced by the plunger while moving the operatingmember toward its second position upon energization of the solenoid; anovercenter spring interconnecting the operating member and the toggleand effective in response to movement of the operating member toward itssecond position to exert a switch closing force on the toggle; andblocking means disposed in cooperation with the operating member forreleasably restraining the switch member in an open circuit positionwhile the operating member is moving toward its second position, saidblocking means being operable as the operating member approaches itssecond position to release the switch memher and permit snap-actionswitch closing movement of the toggle in accordance with the forceexerted by the overcenter spring.

29. In a circuit interrupter: a movable switch member; a toggle havingone end connected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; anoperating member disposed for movement between first and secondpredetermined positions; electroresponsive means for moving theoperating member to its second position comprising a solenoid forproducing a magnetic field when energized, a magnetizable yoke providinga portion of the magnetic circuit for said field and including a polepiece extending into one end of the solenoid, and a magnetizableplunger, providing another portion of the magnetic circuit, disposed formovement into the other end of the solenoid in accordance with magneticforce exerted by said field, said plunger being connected to theoperating member and including a core piece disposed in cooperatingrelationship with said pole piece, said pole piece and core pieces beingconfigured and arranged to reduce the non-linearity of the rate ofincrease of the magnetic force experienced by the plunger while movingthe operating member toward its second position upon energization of thesolenoid; and an overcenter spring interconnecting the operating memberand the toggle and effective in response to movement of the operatingmember to its second position to produce snap-action switch closingmovement of the toggle.

30. A circuit interrupter comprising: a frame mem her; a movable switchmember pivotally supported by the frame member; a toggle having one endconnected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; a movableoperating member mounted on said frame; electromagnetic means for movingthe operating member from first to second predetermined positions, saidelectromagnetic means comprising a solenoid for producing a magneticfield when energized, a magnetizable yoke mounted on said frame anddisposed to support the solenoid, said yoke including a pole pieceextending into one end of the solenoid, and a magnetizable plungerincluding a core piece disposed for longitudinal movement within thesolenoid in accordance with the magnetic force of said field, saidplunger being connected to the operating member for movement thereofupon energization of the solenoid, said pole and core pieces havingcooperating faces one of which is formed with a generally U-shapedrecess for receiving the other with the plunger at the limit of saidlongitudinal movement; an overcenter spring interconnecting theoperating member and the toggle and effective in response to movement ofthe operating member from its first to its second position to producesnapaction switch closing movement of the toggle; means effective duringclosing operation and subsequent thereto for positively preventingmovement of the operating member from its second to its first position;and means responsive to toggle releasing operation of the latching meansfor effecting switch opening movement of the toggle; said means forpreventing movement of the operating member being disposed to permitmovement of the operating member to its first position in response toopening operation.

31. In a circuit interrupter: a frame member; a movable switch memberpivotally supported by the frame member; a toggle having one endconnected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; anoperating member mounted on the frame for movement between first andsecond predetermined positions; electromagnetic means for moving theoperating member comprising a solenoid for producing a magnetic fieldwhen energized, a magnetizable yoke mounted on the frame and disposed tosupport the solenoid, said yoke including a pole piece extending intoone end of the solenoid, a magnetizable plunger including a core piecedisposed for movement into the solenoid at the other end thereof inaccordance with the magnetic force of said field, said plunger beingconnected to the operating member for moving the operating member to itssecond position upon energization of the solenoid, said pole and corepieces having cooperating faces one of which is recessed for receivingthe other thereby to reduce the non-linearity of the rate of increase ofmagnetic force experienced by the plunger while moving the operatingmember toward its second position; an overcenter spring interconnectingthe operating member and the toggle and effective in response tomovement of the operating member toward its second position to exert aswitch closing force on the toggle; and blocking means disposed incooperation with the operating member for releasably restraining theswitch member in an open circuit position while the operating member ismoving toward its second position, said blocking means being operable asthe operating member approaches its second position to release theswitch member and permit snap-action switch closing movement of thetoggle in accordance with the force being exerted by the overcenterspring.

32. In a circuit interrupter: a movable switch member; a releasablylatched operating mechanism connected to the switch member, saidmechanism including a spring arranged to release stored energy forimparting switch closing movement to the mechanism; a movable operatingmember connected to the spring and disposed for movement from first tosecond predetermined positions to control the accumulation of energy bythe spring; and electromagnetic means for moving the operating membercomprising a solenoid for producing 'a 'magnetic field when energized, amagnetizable yoke for the solenoid including a pole piece extending intoone end thereof, and a magnetizable plunger connected to the operatingmember and including a core piece disposed for movement into the otherend of the solenoid under the influence of the force of magneticattraction, said pole and core pieces having cooperating faces one ofwhich is recessed for receiving the other thereby to reduce thenon-linearity of the rate of increase of force of magnetic attractionexperienced by the plunger while moving the operating member toward itssecond position upon energizationof the solenoid.

33. In a circuit interrupter: a switch member disposed for movementbetween open and closed circuit positions; an operating member movablebetween first'and second predetermined positions; a releasably latchedoperating mechanism connected to the switch member, said mechanismincluding a spring connected to the operating member and responsive tomovement of the operating member to its second position for firstaccumulating mechanical energy and then releasing stored energy to themechanism for producing switch closing movement thereof, whereby theswitch member is moved to its closed circuit position; and meansactuated in response to movement of the switch member to its closedcircuit position for blocking the operating member in its secondposition until the switch member returns to its open circuit position.

34: In a circuit interrupter: a switch member disposed for movementbetween open and closed circuit positions; an operating member movablebetween first and second predetermined positions; a releasably latchedoperating mechanism connected to the switch member and including aspring connected to the operating member, said spring being effective inresponse to movement of the operating member from its first positiontoward its second position to accumulate mechanical energy and to exerta switch closing force on the mechanism; blocking means disposed formovement in accordance with the movement of the operating member forpreventing appreciable movement of the switch member toward its closedposition until the operating member reaches a predetermined point nearits second position, whereupon said blocking member moves to a positionwherein it is ineffective to prevent movement of the switch member andthe operating mechanism is able to undergo switch closing movement inaccordance with the force being exerted by the spring; and meansactuated in response to movement of the switch member to its closedcircuit position for blocking the operating member in its secondposition until the switch member returns to its open circuit position.

35. In an electromagnetic device: a solenoid comprising an electric coilwound on the body of a spool of electric insulating material forproducing a magnetic field when energized, said spool having, atopposite ends of its body, respectively, flanges in which transversegrooves are formed; and a magnetizable yoke arranged to support thespool and provide a portion of the magnetic circuit for said field, saidyoke comprising two separable parts between which the spool is clampedwithcooperating transverse portions of the two parts being disposed inthe transverse grooves of the spool flanges; said grooves being deeperat the outer edges of the flanges than in the vicinity of the spool bodywhereby the flanges are relieved of bending stresses when the spool isclamped between the two parts of the yoke.

36. In electromagnetic apparatus for accumulating energy in a springhaving a predetermined spring constant: a pivotally movable operatingmember connected to the spring and disposed to stress the spring uponmovement from a first angular position to a second angular position; asolenoid for producing a magnetic field when energized; a magnetizableyoke disposed to support the solenoid and including a pole pieceextending into one end thereof; a magnetizable plunger positivelycoupled to the operating member and including a core piece disposed formovement into the other end of the solenoid in accordance with magneticforce exerted by said field thereby to move the operating member to itssecond angular position upon energization of the solenoid; and meansguiding the plunger with leeway for lateral deviation thereof whilemoving the operating member toward its second angular position, saidpole and core pieces having cooperating faces configured and arranged toreduce the non-linearity of the increasing magnetic force experienced bythe plunger while moving the operating member toward said secondposition.

37. In a circuit interrupter: a movable switch member; a toggle havingone end connected to the switch member; latching means for releasablyrestraining the other end of the toggle in a latched position; anoperating member disposed for movement between first and secondpredetermined positions; an overcenter spring interconnecting theoperating member and the toggle and effective in response to movement ofthe operating member from its first to its second position to producesnap-action switch closing movement of the toggle; and electromagneticmeans for moving the operating member to its second position comprisinga solenoid for producing a magnetic field when energized, means forsupporting the solenoid, and a magnetizable armature, providing aportion of the magnetic circuit for said field, coupled to the operatingmember and disposed for movement in accordance with magnetic forceexerted by said field upon energization of the solenoid thereby to movethe operating member to its second position.

38. In a circuit interrupter: a movable switch member; a releasablylatched operating mechanism connected to the switch member and includinga spring arranged to release stored energy for imparting switch closingmovement to the mechanism; a movable operating member connected to thespring and disposed for movement from first to second predeterminedpositions to stress the spring, thereby controlling the accumulation ofenergy therein, and to effect said release of stored energy by thespring; and electromagnetic means for moving the operating memberincluding a solenoid for producing a magnetic field when energized,means supporting the solenoid, and a magnetizable armature, comprising aportion of the magnetic circuit for said field, coupled to the operatingmember and disposed for movement in accordance with the force ofmagnetic attraction upon energization of the solenoid thereby to movethe operating member to its second position.

39. In a circuit interrupter: a frame member; a switch member mounted onthe frame member for movement between open and closed circuit positions;a toggle having one end connected to the switch member;-latching meansfor releasably restraining the other end of the toggle in a latchedposition; an operating member mounted on the frame member for movementbetween first and second predetermined positions; electromagnetic meansfor moving the operating member toward its second position comprising asolenoid for producing a magnetic field when energized, said solenoidbeing supported by the frame member, and a magnetizable plunger disposedin the solenoid for longitudinal movement in' accordance with the forceof magnetic attraction, said plunger including a pair of spaced-apartmetallic strips extending from the solenoid in generally parallelrelationship, an elongated metallic extension having one end disposedintermediate the strips where it is releasably keyed and having itsother end positively coupled to said operating member, and removablemeans interconnecting said strips to prevent their spreading apart withsaid extension keyed therebetween; an over-center spring interconnectingthe operating member and the toggle for exerting a switch closing forceat the toggle during movement of the operating member toward its secondposition; and blocking means disposed in cooperation with the operatingand switch members to prevent movement of the switch member to itsclosed position until the opcrating member reaches a predetermined pointnear its second position, whereupon the blocking means is renderedineifective to prevent movement of the switch member and the toggle isable to undergo snap-action switch closing movement in accordance withthe force being exerted by the over-center spring, and to preventmovement of the operating member from its second to its first positionuntil the switch member returns to its open position upon subsequenttoggle releasing operation of the latching means.

40. In a electromagnetic apparatus for actuating a movable member: asolenoid for producing a magnetic field when energized; means disposedto support the solenoid; a magnetizable plunger disposed in the solenoidfor longituduinal movement in accordance with magnetic force exerted bysaid field, said plunger including a pair of spaced-apart metallicstrips extending from the solenoid in generally parallel relationshipand an elongated metallic extension joined at one end to the strips andadapted to be positively coupled at its other end to said movablemember, said one end of the extension being disposed intermediate saidstrips and being releasably keyed thereto; and removable meansinterconnecting said strips to prevent their spreading apart with saidextension keyed therebetween, whereby a rigid junction is maintainedbetween the extension and the strips.

41. The electromagnetic apparatus of claim in which one of thespaced-apart metallic strips is provided with a tapped hole disposed inalignment with a solid portion of the other strip whereby the strips canbe forced apart and the elongated metallic extension released by turninga screw into said tapped hole with the interconnecting means removed.

References Cited in the file of this patent UNITED STATES PATENTS2,539,547 Mossman et al Jan. 30, 1951 2,821,600 Ridgley Jan. 28, 19582,844,682 Furnas July 22, 1958

